At least seven Filipino marines and four Abu Sayyaf militants were killed in a clash yesterday as the military launched an offensive against gunmen blamed for recent kidnappings and of trying to sabotage a road project in the southern Philippines.

Nine other marines and about 10 Abu Sayyaf fighters were wounded in the gun battle that raged for an hour in a sparsely populated village on the fringes of the coastal town of Patikul in Sulu province, military spokesman Brigadier-General Domingo Tutaan said.

Reinforcement troops were hunting down the fleeing militants, who were believed led by Julaswan Sawadjaan, an Abu Sayyaf commander blamed for kidnappings for ransom, including of a Jordanian journalist and two European tourists, who are still held by the militants.

"It was an early morning firefight. Our forces were tracking those responsible for some recent kidnappings in the area," Tutaan said.

A son of Sawadjaan was believed to have been killed in the firefight, said Sulu's military commander, Colonel Jose Cenabre, adding that the marines initially had difficulty returning fire because the militants took cover near a row of houses.

"The close-quarter combat resulted [in] casualties on both sides," he said.

Sawadjaan's men have been accused of this month's kidnapping of a marine's wife who works in a Sulu provincial hospital. The gunmen also recently abducted two government men working on a road project in Patikul. Those two were freed but it was not clear whether a ransom was paid, officials said.

Founded using seed money from al-Qaeda in the 1990s, Abu Sayyaf is blamed for the worst terror attacks in the country, including the firebombing of a ferry in Manila Bay and kidnappings of foreign tourists.

The group is on the US government's list of so-called foreign terrorist organisations.

While Abu Sayyaf abductions still occur, they are far fewer today than the massive kidnappings that terrorised Sulu and outlying provinces in the early 2000s when the group had many commanders and strong ties with terrorist organisations including the Indonesian-based Jemaah Islamiah.

US-backed military offensives have crippled Abu Sayyaf in recent years, but it remains a national security threat.

About 600 US troops have been rotating through the southern Philippines for a decade to help train local troops in hunting Abu Sayyaf, which enjoys local support in some of the poorest areas of the country.

Additional reporting byAgence France-Presse

This article appeared in the South China Morning Post print edition as Marines, militants killed in clash